On Wednesday, 10 August 2016 at 15:25:40 UTC, Lodovico Giaretta
wrote:
Because templated functions cannot be virtual, it follows that
I.func is final. Having no body, the compiler thinks that its
body will be found by the linker in another object file, but
this does not happen, so the linker complains.
Being I.func final, C.func just hides it, so you would not
incur any problem if you called func explicitly on an object of
type C.
So what you found is not a bug, but some unintuitive behaviour
due to templated functions being implicitly final and forward
declarations. Maybe the compiler should emit a warning about
implicitly-final functions in interfaces.
Would it even make sense to "force" (deprecation warning) a
"final" keyword in any implicitly-final function (I wasn't even
aware of those, I have to admit)? It would make things much
clearer, like with "override"...
